another panel update

[Jasper Huijsmans]

hey all,

fyi, from the commit log:

===
* remove builtin launcher
* replace with new launcher (backwards compatible)
* remove popup position global option
* other stuff (it's a pretty big change, so I'm sure i forgot something ;-)

Please tell me if it breaks anything.
===

The new launcher is quite a bit different than the old one, so it may 
take some getting used to:
* popup menu is a real gtk menu widget
* panel item and menu contents can be changed in one dialog
* menu can not be detached. Sorry. If i find a good way to implement 
this I'll add it back.
* position of popup arrow button is no longer configurable.

It seems to use a little less memory, so that's a nice additional 
advantage ;-)

The changes could do with a little testing. Comments, bug reports and 
suggestions are very welcome.

	Jasper